Create root account in webinterface

[xImAnton]

so that installation script is not needed.

For server access verification we could save a token in a local file and require it in the creation form.

The form will show up in the webinterface when no user exists yet.

For checking if a root account exists on the frontend we could use a value in the /config response. Maybe rename that endpoint to /info for consistency.

[xImAnton]

there should be a config option that disables the root user. this could be helpful for testing- and presentation environments.